Discussion: An amplifying high-pressure ridge over Argentina is likely to span extreme heat beginning early next week and intensifying throughout the week. High temperatures are routinely in the 100’s early next week across Argentina. However, searing record-breaking 110’s is projected for middle of next week (Fig. 1). The extreme heat lasts to Monday, January 17th shifting to northern Argentina. Late in the 6-10-day period, a cold front will push into the high-pressure ridge and causes 1-2 in. of rain across Northeast Argentina to East Uruguay (Fig. 2). Temperatures are much cooler south of the front. Dramatic thermal contrast drives the rainfall produced by this dynamic cold front.
The cooling air mass across Argentina in the 11-15-day period pushing up against the hot high-pressure ridge which shifts to Brazil causes widespread significant rain (Fig. 3). The much-needed rain follows a hostile dry and hot stretch.
Does this new pattern continue beyond 15 days? The CFS V2 confirms additional wet risk in Argentina in the 16-20-day period while Brazil is quite dry (Fig. 4).
Fig. 1: The 12Z GFS maximum temperature forecast for Wednesday of next week.
Fig. 2: The 12Z GFS introduces heavy rain at the end of the 6-10-day period.
Fig. 3: The 12Z GFS indicates widespread heavy rain in the 11-15-day period.
Fig. 4: The 16-20-day forecast by CFS V2 favors the wetter Argentina/drier Brazil pattern continuing.